So-so Icarus for Feb 2026 (vol 445):
Rider-Stokes, B. G. Wong, A. Y. C. Burbine, T. H. et al. The Noritic mineralogy of V- and S-type objects and the links with asteroid (4) Vesta Art 116844 /j.icarus.2025.116844
Castro-Cisneros, J. D. Malhotra, R. Rosengren, A. J. Analytical estimates for heliocentric escape of satellite ejecta Art 116845 .2025.116845
Marshall-Lee, A. Christou, A. Delbo, M. et al. Characterising the efficiency of the hierarchical clustering method Art 116862 .2025.116862
Fernández, J. A. The depletion of the asteroid belt and the impact history of the Earth Art 116824 .2025.116824
We have (4) Vesta (courtesy of the Dawn mission). We have HED meteorites, clearly from some volcano-differentiated body (like Vesta). And in between, we have small asteroids, forming a “trail”(in terms of celestial mechanics) away from Vesta. How strong are these links? We cannot simply assume the chain is a valid one because it looks valid.
Asteroids lose ejecta in impacts (natural or manmade). Some low-speed ejecta forms fallback, and moderate-speed ejecta may form satellites. Just how much leaves the ‘system’ entirely? Castro-Cisneros et al. tackle the valid issue- in the long term, asteroids grind away to nothing.
The hierarchical clustering method is how we trace that ejecta back to its parent body(s). Given one or more asteroids in a putative asteroid family, how do we measure “family-ness”- are they actually fragments from an impact event on a parent? Or just coincidentally in close orbits?
And speaking of grinding away, the Main Asteroid Belt was surely much thicker and denser in the past. How much so, and how fast did it grind down to today’s state? It’s far from a settled question- this affects the formation and alteration of the planets in the young Solar System, and later effects such as the delivery of water and other life ingredients. Fernández et al. don’t literally close the case, but it’s a very interesting result.